Assessment of the spatial variability in particulate organic matter and mineral sinking fluxes in the ocean interior: Implications for the ballast hypothesis
Assessment of the spatial variability in particulate organic matter and mineral sinking fluxes in the ocean interior: Implications for the ballast hypothesis
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DOI：
10.1029/2012gb004398
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发表时间：
2012-12
影响因子：
5.2
通讯作者：
Jamie D. Wilson;S. Barker;A. Ridgwell
中科院分区：
文献类型：
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作者：
Jamie D. Wilson;S. Barker;A. Ridgwell
应用于沉积物捕集器数据的多元线性回归分析(MLRA)在确定合理的“压载”机制方面具有很大的影响力，该机制将颗粒有机碳(POC)的沉降通量与密度较高的无机矿物的沉降通量直接联系起来。然而，迄今为止的分析主要是在全球范围内进行的，在通量关系中遗漏了可能重要的空间变异性。本文利用Klaas和Archer(2002)的MLRA方法，将地理加权回归(GWR)应用于一个更新的深部(>；1500 m)沉积物圈闭数据库(n=156)，但现在允许携带系数在空间上变化。虽然CaCO3、蛋白石和成岩作用的全球平均携带系数值与以前的工作大体一致，但GWR分析显示，所有这三种携带系数都存在显著的空间变异性。特别是，在我们的空间分析中，CaCO3和POC之间缺乏强大的全球统一关系，这让人怀疑是否存在简单的压载机制。相反，携带系数存在连贯的空间模式，这让人想起生物地球化学省，这表明特定的远洋生态系统特征的差异可能是沉积物陷阱采样的通量关系的根本原因。我们的发现对海洋碳循环模型师提出了挑战，他们在考虑矿物压载时，迄今在其碳通量参数中应用了单一的统计全球关系，并为现代海洋中生物泵的效率如何调节提供了进一步的线索。
Multiple linear regression analysis (MLRA) applied to sediment trap data has been highly influential in identifying a plausible ‘ballasting’ mechanism that directly links the settling fluxes of particulate organic carbon (POC) to those of denser, inorganic minerals. However, analysis to date has primarily been carried out at the global scale, missing spatial variability in the flux relationships that may be important. In this paper, Geographically Weighted Regression (GWR) is applied to an updated deep (>1500 m) sediment trap database (n = 156), using the MLRA approach of Klaas and Archer (2002) but now allowing the carrying coefficients to vary in space. While the global mean carrying coefficient values for CaCO3, opal, and lithogenics are broadly consistent with previous work, the GWR analysis reveals the existence of substantial and statistically significant spatial variability in all three carrying coefficients. In particular, the absence of a strong globally uniform relationship between CaCO3 and POC in our spatial analysis calls into question whether a simple ballasting mechanism exists. Instead, the existence of coherent spatial patterns in carrying coefficients, which are reminiscent of biogeochemical provinces, points toward differences in specific pelagic ecosystem characteristics as being the likely underlying cause of the flux relationships sampled by sediment traps. Our findings present a challenge to ocean carbon cycle modelers who to date have applied a single statistical global relationship in their carbon flux parameterizations when considering mineral ballasting, and provide a further clue as to how the efficiency of the biological pump in the modern ocean is regulated.